This invention relates generally to developing electrostatic charge patterns, and more particularly to transporting successive discrete electrographic sheets, respectively carrying electrostatic charge patterns, seriatim into pattern-developing relation with a developer station.
In the copending commonly assigned U.S. Pat. No. 4,436,405 patented Mar. 13, 1984 in the names of Kindt et al, an electrographic copier apparatus is described utilizing a plurality of electrographic film sheets. The copier makes monochrome reproductions, or multicolor reproductions of a multicolor document, by forming electrostatic charge patterns on the film sheets respectively corresponding to the image of the monochrome document or to the related color separation images of the multicolor document. The film sheets are transported seriatim about a track assembly into operative relation with electrographic process stations. In the process stations, the charge patterns are respectively developed with pigmented electroscopic marking particles (for example, black for monochrome reproduction, or complementary primary colors for multicolor reproduction) to form transferable images. In monochrome reproduction, the images are respectively transferred to receiver members and then fixed (fused) to such members to form the reproductions. In making a multicolor reproduction, related transferable images (corresponding) to the color separation images of a multicolor document are transferred seriatim onto a receiver member in accurate superimposed register and then fixed to such member to form the multicolor reproduction of the document.
Development of the electrostatic charge patterns is typically accomplished with magnetic brush developer stations such as shown in U.S. Pat. No. 3,703,395 issued Nov. 21, 1972 in the names of Drexler et al for example. Each developer station includes an applicator having a brush nap of electroscopic marking particles and ferromagnetic carrier particles which is contacted by respective film sheets. The marking particles from the brush naps are attracted to the respective film sheets by the electrostatic charge patterns on such sheets. However, as the film sheets are transported through the developer apparatus, there is a tendency for the film sheets to plow through the brush naps resulting in the undesirable depositing of marking and carrier particles on the back side of the sheets.